Analogy in Classical Greece

The aim of this book is to analyse and defend the claim that the first four chapters of Darwin’s Origin constitute an argument by analogy from artificial selection to natural selection, situating that argument in Darwin’s thought as a whole: just as human beings by their selective practices in domestic settings can make new varieties of plants and animals, so the struggle for existence in the wild can make new varieties and even new species of plants and animals. This claim has been frequently made, but also latterly contested. However, both the defenders and the opponents rarely spell out in detail what the argument is supposed to be, and, insofar as they do so, usually work with an inappropriate account of what an argument by analogy is thought to be. Therefore, before turning to Darwin himself, we need, in this chapter and the next, to examine the idea of an argument by analogy. We begin in classical Greece where the concept of analogy was introduced, before turning in the next chapter to the emergence of a completely different conception of analogy, and with it a completely different account of argument by analogy. We shall argue that although the later account has become the most popular understanding of ‘argument by analogy’, it is the classical account which is the appropriate one to account for the text of the Origin. The point is that the word ‘analogy’ has historically been understood in two quite different ways. The word was initially introduced in Pythagorean mathematics (‘ἀναλογια’) and then extended into the empirical domain, above all by Aristotle. Here, the word always designated a proportionality (‘A is to B as C is to D’), and the interest was in the rich variety of uses to which appeals to analogies of this kind could be put, as against simple similarities (‘A and B share some intrinsic properties’), whose uses were very limited. The contrast between analogy and simple similarity was always observed and insisted upon. However, beginning in the seventeenth century, in large part as a reaction against mediaeval scholasticism, this